1. Field of the Invention:
The present invention relates generally to engine carburetors, and more particularly, to an ultrasonic wave carburetor which may instantaneously atomize liquid fuel and mix the same with air by means of an ultrasonic vibratory member, having a hollow cylindrical body structure, which is positioned downstream of a venturi portion, thereby supplying a uniform air-fuel mixture to a combustion chamber of an engine.
2. Description of the Prior Art:
Prior art carburetors suffer from a failure in atomizing the fuel in an unsatisfactory manner, that is, in not continuously supplying a uniform air-fuel mixture to the respective cylinders of an automotive engine over the entire operational range of the automobile, extending from low speed to high speed conditions. This is particularly true with low-speed running of the engine, because poor fuel atomization results due to a low flow speed of the air streams travelling through the venturi portion, whereby the majority of the fuel clings to the wall of the passage, and the fuel in the form of liquid is produced thereon and flows along the wall of the passage. This is responsible for the aforenoted failure in achieving a uniform air-fuel mixture.
In light of such circumstances, many attempts have been proposed for the purpose of supplying a uniform air-fuel mixture to the engine in order to improve the engine performance and purify the exhaust gases. Typical of these are a carburetor of the type in which an electric heat-generating means is provided in the intake passage for gasifying the fuel by heat; a carburetor in which a heater utilizing the heat of the exhaust gases from the engine is provided for promoting gasification of the fuel by heat; a carburetor which is provided with a fuel atomizing means; and the like.
However, prior art carburetors using an electric heater pose the problem of needing to supply, by using the heater, an enormous amount of heat per unit time for gasifying the liquid fuel passing, in the form of streams, through the carburetor. This leads to the use of a great amount of electric power, and hence, difficulty in providing a practicable carburetor for an automobile.
The carburetor of this type also fails to maintain the provisions of a uniform air-fuel mixture because the flow rate of the liquid fuel passing through the heater is extremely varied under conditions wherein acceleration and deceleration are continuously repeated as in the case of an automotive engine, or the like. In addition, with an engine, in general, when the temperature of the air-fuel mixture is increased, the charging efficiency of the fuel is lowered, with an accompanying lowering of the output of the engine. It follows from this that the aforenoted carburetor necessarily suffers in lowering the output of the engine, because gasification of the fuel is accompanied by an increase in the temperature of the air-fuel mixture.
Similarly, with prior art carburetors for gasifying fuel by utilizing the heat of the exhaust gases from the engine, difficulty is confronted with starting the engine during cold weather and poor gasification of the fuel by means of a heater because the temperature of the exhaust gases is relatively low for a predetermined period of time immediately after starting the engine. Furthermore, heating means utilizing the heat of the exhaust gases are normally of complex construction in order to maintain desired functions and safety. Still further, a carburetor of this type tends to lower the output of the engine due to the fact that gasification of the fuel due to the heat of the exhaust gases is necessarily accompanied by an increase in the temperature of the air-fuel mixture with the resulting difficulty in controlling the temperature of the heater.
With a carburetor equipped with an ultrasonic wave fuel atomizing means, the atomizing area is normally insufficient, so that only a small amount of the fuel may be atomized per unit time, and a great amount of electric power is required for generating the ultrasonic waves, thus failing to meet the requirements arising from the practical application of the engine. Furthermore, prior art ultrasonic atomizing technology is only partially successful in providing an excessively large-sized atomizing means for achieving the desired atomization of the fuel for the engine, while suffering from the difficulty in not generating ultrasonic waves for a long period of time with high reliability, as well as from an increase in size of the carburetor, with an accompanying complexity of its construction.